Installations of this type are known particularly from such busses, called `ski-busses`, which are long-distance busses, for the operation of which it is necessary that they can drive both day and night and that the travellers can spend the night reasonably comfortably for effective sleep, that is on real, horizontal bed units.
These chairs should be correspondingly particularly designed partly with strong, upright supports for carrying the upper bed row and partly with extra cushion elements for filling in the spaces between the seats in the lower bed row. The chairs are mounted in pairs, side by side, and the upstanding supports may thus be formed by a single carrier for each pair of chairs. The carrier member should project so far upwardly that an upper, horizontal part thereof can carry the associated, swung-up back rests, and typically this height will be underneath the top edge of the back rest of an ordinary train or bus chair. For this reason it is natural that the upper carrier member be used not only as a carrier member, but also as a shaft for the swinging up of the back rest, the upper, horizontal carrier portion hereby being connected with the rear side of the back rest in a manner such that the back rest is fixed to and supported by the upper carrier portion in both the sitting and the lying position.
It will facilitate the conversion of the chair that the back rest can thus simply be swung about the fixed carrier portion for making the conversion, and it is an accepted associated drawback that each pair of chairs, when seen from behind, appears with a heavily dimensioned cross rod across an upper part of the back rest, this being unusual for ordinary chairs.
Given that the back rests should play a very important roll as bed elements it has been customary to design the back rests almost primarily as bed elements, i.e. with flat front sides that will form flat couches in the swung-up position. Hereby, of course, the back rests will be perfect as bed elements, but in return they are rather unsuitable as back rests in chairs, inasfar as in this area it is normal to aim at a special ergonomical design of the back rest and moreover to design the back rest with a look more elegant than only an upstanding, rectangular plate block that is functionally well suited to form part of an upper, continuous row of beds.
To the paying customers all this will be acceptable in situations in which it is of main importance that the transportation can take place as a long tour e.g. to and from a skiing site, but just this typical example will show that the relevant activities may well be largely season conditioned, while outside these relative short periods, concerning the application of the vehicle, it will be unrealistic to offer to the passengers a correspondingly low seating comfort and an associated clumsy look of the back rests. This is a reality to the degree that it is a quite common practice that the bus owners every year, at the beginning and the end of the skiing season, carry out a total change of the entire chair installation of the vehicle, such that outside the particular season it is possible to drive with more usual, nice-looking and more user friendly chairs for servicing non-sleeping passengers. These changings, however, are rather costly.